Improvement in lettee-balanoes



@eine faire item1 @Him 'BENJAMIN CHAMBERS, Je., or'wAsHiNeToN-DISTRIGT 0F COLUMBIA.

` Letters PatentNo. 75,244, dated Marck 10, 1868.

IMPROVEMENT IN IETTERPBALANGII'S.

@lure-.prlgehnl-rfemh tain time Eaters @anni with melting p21-rt uitte sume.

TO LL WHOMIT MAY CONCERN:

Be it known that I, BENJAMINjCIMBEIiS, Jr., .of the cityof Washington, inthe District of- Columbia, have invented a certain new and useful 'Improvement on Letter-Balances and I d o hereby declare that the following is a full, clear, and exact description thereof', reference being had to the accompanying drawings, and to the.

letters and marks thereon, which said'drawings form part of this specication, and represent a letter-balance constructed under my invention- Figure 1 thereof being a side view.-

-liigureQ, an end view.

Figure 3, a top view; and

Figure a side view' of one of the lugs supporting the knife-edge. 4

In eaclrof these figures, where like parts are shown, like marks and letters are used to indicate the parts.

As usually construc ted,`the disha of the letter-balance is aihxed to the beam b at or near its centre. When se aihxed or attached, thedishis apt to tilt when any vweight or letter or package to be weighed is placed near its edge or corners, so that in the 'hurry and dispatch of'business the weighing ofthe letters and packages will blo imperfect and incorrect; In order to remedy-this objection to letter-balances, I make the bcamt, at its dish-` end, forked, as is plainly indcated'by the dotted lines of iig. 3, The forking of the beam allowsthe lugs in which the knife-edges play to be placed towards the ends of the dish, thnsaiording a steady-alud broadbearing to the dish, and when the weight or package or letter to b'e weighed is thrown on the Aedge or corner of the 'dish the weighing will ,be asfperfect and accurate as when thrown onthe centre of the dish. The lugs of the dish are marked c, the forked ends ofthe beam el, and the knife-edges e. From the middle of the fork a rod, i, passes out towards a vertical rod,f, attached at its upper end to the centre offthe dish, and its lower jointed to a horizontal vibrating-rod, which is also jointed to a rod placed vertically, and permanently xed inside of the base, g; This arrangement of rods-.is fully shown by figs.. 1, 2, and 3. On. the horizontal'rod is placed a regulatingnut, 7i, that by means of scr ewthreads can be-moved back and forth, and thus keeping thebalance always in trim whenI the weight i is at 0. 'The balancing knife-edges j of the beam have their bearings inuprights 7c,-

from the top of the base-block g, which uprights are of 'one continuous piece of metal, as shown by iig. 2, the middle of the'vpiece being attached to the top'of thebase-block bya screw or its equivalent. The bearings of the knifel'edges j are in holes -n the uprightsk, so that the whole balance can be lifted upby the beam, the knife-edges keeping inthe holes. The knife-edges are prevented passing out endwise through the`holes by smalliplates covering the holes, the plate of one side being pivoted, as shown by iig. 4, and when this plato is turned up, as there shown, the beam can b e removed from the uprights. The 'graduated scale, as is shown by iig. l, is

upon the side of the beain b, the notches being on the top edge of the beam, and the weight z', by a hole or slot, allows to be moved back and forth on the beam. The kn'ifcedges e are fitted in the holes oi' the lugs c, like the knife-edges j, having the plates to cover the holes, oneof which may be pivoted, as shown by iig. 4,. so as to allow the dish to be removed from the beam. The beam b, I usually make by casting it as one piece of metal, the ears m, -through which the balancing knife-edges pass, and the forked ends d, being a part thereof.

What I claim as my invention, and desire to secur'c by Letters Patent, is-

The knife-edges in holes passing through the lugs, as herein described, and covered, the covering plate at one end being pivoted, whereby the knife-edges are kept in place, and can be readily removed when itis required to remove them. I

This specification signed this 30th day of January, 1868.

' B. CHAMBERS, JR. Witnesses;

Tiros. T. Evensr'r, THos. T. PARKER. 

